EP0093319B1 - Process for the electrolytic production of chlorine and caustic soda from salt containing sulphate - Google Patents

Process for the electrolytic production of chlorine and caustic soda from salt containing sulphate Download PDF

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Publication number
EP0093319B1
EP0093319B1 EP83103829A EP83103829A EP0093319B1 EP 0093319 B1 EP0093319 B1 EP 0093319B1 EP 83103829 A EP83103829 A EP 83103829A EP 83103829 A EP83103829 A EP 83103829A EP 0093319 B1 EP0093319 B1 EP 0093319B1
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Prior art keywords
brine
partial stream
stream
sulphate
salt
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German (de)
French (fr)
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EP0093319A2 (en
EP0093319A3 (en
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Rolf Dr. Schäfer
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Bayer AG
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Bayer AG
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B15/00—Operating or servicing cells
    • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes

Definitions

  • the present invention relates in particular to processes for the electrolytic production of chlorine and sodium hydroxide solution from sulfate-containing salt, in which the brine is circulated.
  • the impurities in the salt are enriched in the brine circuit if they are not removed by continuous cleaning operations except for residual levels that are tolerable during electrolysis. After passing through the electrolysis cell, the brine is acidified and dechlorinated. In the further course of the brine cycle, there are process and plant-related variants. The majority of large-scale plants are still amalgam plants, most of them have open salt dissolving stations. In this case, an alkalization of the brine is required before reactivation in order to safely avoid emissions of residual chlorine. Usually, the necessary excess of sodium hydroxide solution is added at the time of re-saturation, so that the hydroxides of magnesium and iron also precipitate out during the dissolving process.
  • Calcium carbonate and barium sulfate are then precipitated by adding barium compounds and soda. Soda and caustic soda are used in excess in order to achieve the most complete precipitation possible. Barium compounds are added in the deficit so that they are fully implemented.
  • a certain sulfate content in the brine is tolerable. In the membrane process, the tolerable limit of a few g / l is determined by the membranes currently available. It is expected that sulfate-resistant membranes will also be available in the future. In the case of the amalgam process with graphite anodes, the graphite burnup, which increases with the sulfate content, determines the upper limit. When using titanium anodes, relatively high sulfate contents of up to 30 g sulfate / l can be controlled in the amalgam process.
  • a process for sulfate removal without precipitation chemicals for converting sodium sulfate-containing sodium chloride salt into a NaCl brine which can be used in the diaphragm process and is largely reduced in sulfate content.
  • the sulfate-containing salt is partially dissolved in water, resulting in an aqueous solution containing Na 2 SO 4 / NaCl and solid, pure NaCl. Pure Glauber's salt is separated from the solution by cooling crystallization, the remaining NaCl solution, which is reduced in sulfate content, can be recycled into the electrolysis.
  • EP-A-8470 It is also known from EP-A-8470 to prevent an accumulation of chlorate in the brine circuit by partial flow treatment of an alkali halide-containing solution with hydrochloric acid, halogen oxyacids / salts being broken down to an acceptable level.
  • the object of the present invention is to provide a process which does not require the relatively expensive barium compounds for sulfate precipitation and in which there are also no difficulties in removing the other impurities such as magnesium and iron.
  • the sulfate can be removed from the circulating brine under certain additional conditions as a Glauber's salt by cooling crystallization without adversely affecting the electrolysis process.
  • the present invention accordingly relates to the combination of Glauber's salt cooling crystallization precipitation, chlorate removal and the precipitation of the further impurities.
  • the embodiment of the process according to the invention is particularly preferred in which, after the brine has been re-strengthened, the calcium ions introduced as an impurity with the salt are first precipitated as calcium carbonate and then further impurities are precipitated by adding sodium hydroxide, and that Precipitated is filtered off together. This results in an excellent filterable brine.
  • the possible accumulation of chlorate in the brine circuit can be avoided within a few minutes by decomposing the chlorate with a relatively high excess of hydrochloric acid.
  • the chlorate removal from a partial stream is sufficient to keep the chlorate content in the brine circuit at a tolerable value.
  • it is sufficient to keep the partial flow for the chlorate removal in the order of magnitude for the amount of hydrochloric acid necessary for the acidification for the dechlorination.
  • the volume flow of the first partial flow is preferably about half to double the volume flow of hydrochloric acid. 15 to 25%, more preferably about 20%, hydrochloric acid is preferably used. Hydrochloric acid diluted in this way is still sufficient to bring about chlorate decomposition.
  • Glauber's salt precipitation can be carried out according to known laws without any problems.
  • the strong dependence of the solubility of the Glauber's salt in concentrated brine on the temperature is known.
  • the solubility of Glauber's salt, expressed in g SOJI is approx. 15 at 5 ° C and approx. 10 at 0 ° C.
  • the parameters determining the Glauber's salt cooling crystallization precipitation can be specified in a simple manner for the other parameters present in a technical electrolysis cell.
  • a sodium chloride salt with 0.5% sulfate content is also used to strengthen a brine that has been depleted in the electrolysis cell by 40 g / l, so a partial flow of 2% of the brine flow to 5 ° C to cool so that the sulfate introduced when 40 g of salt are dissolved per 1 brine is removed. With more cooling, the partial flow for the cooling crystallization can be kept smaller.
  • the brine in this second partial stream is preferably cooled to temperatures between -5 and 10 ° C., particularly preferably to temperatures between 0 and 5 ° C.

Description

Für die elektrolytische Herstellung von Chlor und Natronlauge stehen verschiedene Verfahren zur Verfügung : Das Diaphragma-, das Amalgam-und neuerdings das Membran-Verfahren. Üblicherweise wird insbesondere bei den beiden zuletzt genannten Verfahren die Sole im Kreis geführt, wobei beim Durchgang durch die Elektrolysezelle ein Teil des Salzes zersetzt wird und die in der Elektrolysezelle verarmte Sole durch Auflösen von festem Salz wieder aufgestärkt wird.Various processes are available for the electrolytic production of chlorine and sodium hydroxide solution: the diaphragm, the amalgam and more recently the membrane process. Usually, in particular in the latter two methods, the brine is circulated, part of the salt being decomposed as it passes through the electrolytic cell and the brine depleted in the electrolytic cell being strengthened again by dissolving solid salt.

Die vorliegende Erfindung bezieht sich insbesondere auf Verfahren zurelektrolytischen Herstellung von Chlor und Natronlauge aus sulfathaltigem Salz, bei denen die Sole im Kreislauf geführt wird.The present invention relates in particular to processes for the electrolytic production of chlorine and sodium hydroxide solution from sulfate-containing salt, in which the brine is circulated.

Die Verunreinigungen des Salzes werden im Solekreislauf angereichert, wenn sie nicht durch fortlaufende Reinigungsoperationen bis auf bei der Elektrolyse tolerierbare Restgehalte entfernt werden. Nach Durchlaufen der Elektrolysezelle wird die Sole angesäuert und entchlort. Im weiteren Verlauf des Solekreislaufs gibt es dann verfahrens- und anlagenbedingte Varianten. Die Mehrzahl der großtechnischen Anlagen sind bis heute Amalgamanlagen, die meisten von ihnen haben offene Salzlösestationen. In diesem Fall ist vor der Wiederaufsätigung eine Alkalisierung der Sole erforderlich, um Emissionen von Restchlor sicher zu vermeiden. Üblicherweise wird der erforderliche Natronlaugeüberschuß bei der Wiederaufsättigung gleich mit zugegeben, so daß die Hydroxyde von Magnesium und Eisen schon während des Lösevorganges mit ausfallen. Anschließend wird durch Zugabe von Bariumverbindungen und Soda Calciumcarbonat und Bariumsulfat gefällt. Soda und Natronlauge werden im Überschuß angewandt, um möglichst vollständige Fällung zu erreichen. Bariumverbindungen werden im Unterschuß zugesetzt, damit diese vollständig umgesetzt werden. Ein gewisser Sulfatgehalt in der Sole ist tolerierbar. Die tolerierbare Grenze von wenigen g/I wird beim Membranverfahren durch die derzeit verfügbaren Membranen bestimmt. Es ist zu erwarten, daß in Zukunft auch sulfatfeste Membranen zur Verfügung stehen werden. Beim Amalgamverfahren mit Graphitanoden bestimmt der mit dem Sulfatgehalt steigende Graphitabbrand die obere Grenze. Beim Einsatz von Titananoden sind relativ hohe Sulfatgehalte bis zu 30 g Sulfat/I beim Amalgamverfahren beherrschbar.The impurities in the salt are enriched in the brine circuit if they are not removed by continuous cleaning operations except for residual levels that are tolerable during electrolysis. After passing through the electrolysis cell, the brine is acidified and dechlorinated. In the further course of the brine cycle, there are process and plant-related variants. The majority of large-scale plants are still amalgam plants, most of them have open salt dissolving stations. In this case, an alkalization of the brine is required before reactivation in order to safely avoid emissions of residual chlorine. Usually, the necessary excess of sodium hydroxide solution is added at the time of re-saturation, so that the hydroxides of magnesium and iron also precipitate out during the dissolving process. Calcium carbonate and barium sulfate are then precipitated by adding barium compounds and soda. Soda and caustic soda are used in excess in order to achieve the most complete precipitation possible. Barium compounds are added in the deficit so that they are fully implemented. A certain sulfate content in the brine is tolerable. In the membrane process, the tolerable limit of a few g / l is determined by the membranes currently available. It is expected that sulfate-resistant membranes will also be available in the future. In the case of the amalgam process with graphite anodes, the graphite burnup, which increases with the sulfate content, determines the upper limit. When using titanium anodes, relatively high sulfate contents of up to 30 g sulfate / l can be controlled in the amalgam process.

Aus der FR-A-2376907 ist ein Verfahren zur Sulfatentfernung ohne Fällungschemikalien bekannt, natriumsulfathaltiges Nätriumchloridsalz in eine im Diaphragmaverfahren einsetzbare, im Sulfatgehalt weitgehend reduzierte NaCI-Sole zu überführen. Dazu wird das sulfathaltige Salz teilweise in Wasser gelöst, wobei eine Na2S04/NaCI-haltige wäßrige Lösung und festes reines NaCI resultieren. Aus der Lösung wird durch Kühlungskristallisation reines Glaubersalz abgeschieden, die verbleibende, im Sulfatgehalt verminderte NaCI-Lösung kann in die Elektrolyse rezykliert werden.From FR-A-2376907 a process for sulfate removal without precipitation chemicals is known for converting sodium sulfate-containing sodium chloride salt into a NaCl brine which can be used in the diaphragm process and is largely reduced in sulfate content. For this purpose, the sulfate-containing salt is partially dissolved in water, resulting in an aqueous solution containing Na 2 SO 4 / NaCl and solid, pure NaCl. Pure Glauber's salt is separated from the solution by cooling crystallization, the remaining NaCl solution, which is reduced in sulfate content, can be recycled into the electrolysis.

Auch ist es aus der EP-A-8470 bekannt, eine Anreicherung von Chlorat im Solekreislauf zu verhindern durch eine Teilstrombehandlung einer Alkalihalogenid-haltigen Lösung mit Salzsäure, wobei Halogen-Sauerstoffsäuren/salze auf ein vertretbares Maß abgebaut werden.It is also known from EP-A-8470 to prevent an accumulation of chlorate in the brine circuit by partial flow treatment of an alkali halide-containing solution with hydrochloric acid, halogen oxyacids / salts being broken down to an acceptable level.

Aufgabe der vorliegenden Erfindung ist es, ein Verfahren bereitzustellen, das ohne die relativ teuren Bariumverbindungen zur Sulfatfällung auskommt und bei dem es auch bei der Entfernung der übrigen Verunreinigungen wie Magnesium, Eisen nicht zu Schwierigkeiten kommt.The object of the present invention is to provide a process which does not require the relatively expensive barium compounds for sulfate precipitation and in which there are also no difficulties in removing the other impurities such as magnesium and iron.

Es wurde gefunden, daß das Sulfat aus der im Kreislauf geführten Sole unter bestimmten weiteren Bedingungen als Glaubersalz durch Kühlungskristallisation entfernt werden kann, ohne daß das Elektrolyseverfahren negativ beeinflußt wird.It has been found that the sulfate can be removed from the circulating brine under certain additional conditions as a Glauber's salt by cooling crystallization without adversely affecting the electrolysis process.

Gegenstand der vorliegenden Erfindung ist nun ein Verfahren zur Herstellung von Chlor und Natronlauge aus sulfathaltigem Natriumchloridsalz durch Elektrolyse, bei dem eine sulfathaltige Natriumchloridsole im Kreislauf geführt wird zwischen Verarmung der Sole an Natriumchlorid in der Elektrolysezelle und Wiederaufstärkung der Sole durch Auflösung von sulfathaltigem Salz, wobei die Sole nach Verlassen der Elektrolysezelle durch Ansäuern mit Salzsäure entchlort wird und das mit dem Salz in die Sole eingeführte Sulfat sowie weitere Verunreinigungen aus der Sole entfernt wird, dadurch gekennzeichnet, daß

  • a) aus dem Solekreislauf ein erster Teilstrom abgezweigt wird, zu dem die zum Ansäuern der Sole notwendige Salzsäure zugegeben wird, der Teilstrom nach einer Verweilzeit die zur Zersetzung des bei der Elektrolyse gebildeten, in dem Teilstrom enthaltenen Chlorats ausreicht, mit dem Solehauptstrom vereinigt wird, und
  • b) aus dem Solestrom ein zweiter Teilstrom abgezweigt wird, der zweite Teilstrom derart gekühlt wird, daß eine dem gesamten in die Sole eingeführten Sulfat entsprechende Menge Na2S04 . 10H20 auskristallisiert, der Kristallbrei abgetrennt und der zweite Teilstrom mit dem Sole-Hauptstrom wiedervereinigt wird, und
  • c) daß die Sole zur Wiederaufstärkung durch Zugabe von Natriumhydroxid auf einen pH-Wert von 6 bis 8,5 eingestellt wird.
The present invention now relates to a process for the production of chlorine and sodium hydroxide solution from sulfate-containing sodium chloride salt by electrolysis, in which a sulfate-containing sodium chloride brine is circulated between depletion of the sodium chloride brine in the electrolysis cell and re-strengthening of the brine by dissolving sulfate-containing salt, the After leaving the electrolysis cell, the brine is dechlorinated by acidification with hydrochloric acid and the sulfate introduced with the salt into the brine and other impurities are removed from the brine, characterized in that
  • a) a first partial stream is branched off from the brine circuit, to which the hydrochloric acid necessary for acidifying the brine is added, the partial stream is combined with the main brine stream after a dwell time which is sufficient to decompose the chlorate formed in the partial stream during electrolysis, and
  • b) a second partial stream is branched off from the brine stream, the second partial stream is cooled in such a way that an amount of Na 2 S0 4 corresponding to the total sulfate introduced into the brine. 10H20 crystallized, the crystal slurry separated and the second partial stream is reunited with the brine main stream, and
  • c) that the brine is re-strengthened by adding sodium hydroxide to a pH of 6 to 8.5.

Gegenstand der vorliegenden Erfindung ist demnach die Kombination aus Glaubersalz-Kühlungskristallisations-fällung, Chloratentfernung und der Fällung der weiteren Verunreinigungen. Besonders bevorzugt ist die Ausführungsform des erfindungsgemäßen Verfahrens, bei der nach der Wiederaufstärkung der Sole zunächst durch Zugabe von Soda die als Verunreinigung mit dem Salz eingeführten Calciumionen als Calciumcarbonat und danach durch weitere Zugabe von Natriumhydroxid weitere Verunreinigungen gefällt werden und das Gefällte gemeinsam abfiltriert wird. Hierdurch ergibt sich eine ausgezeichnet filtrierbare Sole.The present invention accordingly relates to the combination of Glauber's salt cooling crystallization precipitation, chlorate removal and the precipitation of the further impurities. The embodiment of the process according to the invention is particularly preferred in which, after the brine has been re-strengthened, the calcium ions introduced as an impurity with the salt are first precipitated as calcium carbonate and then further impurities are precipitated by adding sodium hydroxide, and that Precipitated is filtered off together. This results in an excellent filterable brine.

Die gegebenenfalls auftretende Anreicherung von Chlorat im Solekreislauf kann durch eine Zersetzung des Chlorats bei relativ hohem Salzsäureüberschuß innerhalb von wenigen Minuten vermieden werden. Die Chloratentfernung aus einem Teilstrom reicht aus, um den Chloratgehalt im Solekreislauf auf einem tolerierbaren Wert zu halten. Insbesondere ist es ausreichend, den Teilstrom für die Chloratentfernung mengenmäßig in der Größenordnung für das Ansäuern zur Entchlorung notwendigen Menge Salzsäure zu halten. Bevorzugt beträgt der Volumenstrom des ersten Teilstrom etwa die Hälfte bis zum Doppelten des Volumenstroms der Salzsäure. Bevorzugt wird 15 bis 25 %ige, besonders bevorzugt etwa 20 %ige, Salzsäure eingesetzt. Eine so verdünnte Salzsäure ist noch ausreichend, um die Chloratzersetzung zu bewirken. Bei höherkonzentrierter Salzsäure kann es zur Ausfällung von festem Natriumchlorid kommen. In einem technischen Prozeß wird zum Verdünnen der Salzsäure zweckmäßigerweise Kondensat aus der Chlorkühlung abgezweigt, das aus Umweltschutzgründen ohnehin der Sole wieder zugeführt wird. Der Soleteilstrom, in dem die Chloratentfernung erfolgt, beträgt beispielsweise ca. 0,5 bis 2 % des Solehauptstroms.The possible accumulation of chlorate in the brine circuit can be avoided within a few minutes by decomposing the chlorate with a relatively high excess of hydrochloric acid. The chlorate removal from a partial stream is sufficient to keep the chlorate content in the brine circuit at a tolerable value. In particular, it is sufficient to keep the partial flow for the chlorate removal in the order of magnitude for the amount of hydrochloric acid necessary for the acidification for the dechlorination. The volume flow of the first partial flow is preferably about half to double the volume flow of hydrochloric acid. 15 to 25%, more preferably about 20%, hydrochloric acid is preferably used. Hydrochloric acid diluted in this way is still sufficient to bring about chlorate decomposition. With more concentrated hydrochloric acid, solid sodium chloride can precipitate. In a technical process, to dilute the hydrochloric acid, condensate from the chlorine cooling is expediently branched off, which is returned to the brine anyway for environmental reasons. The partial brine flow in which the chlorate removal takes place is, for example, approximately 0.5 to 2% of the main brine flow.

Ist die Entfernung von Chlorat aus dem Solekreislauf sichergestellt, kann die Glaubersalzfällung völlig unproblematisch nach bekannten Gesetzmäßigkeiten erfolgen. Die starke Abhängigkeit der Löslichkeit des Glaubersalzes in konzentrierter Sole von der Temperatur ist bekannt. Zum Beispiel beträgt die Löslichkeit des Glaubersalzes, angegeben in g SOJI, bei 5 °C ca. 15 und bei 0 °C ca. 10.If the removal of chlorate from the brine circuit is ensured, Glauber's salt precipitation can be carried out according to known laws without any problems. The strong dependence of the solubility of the Glauber's salt in concentrated brine on the temperature is known. For example, the solubility of Glauber's salt, expressed in g SOJI, is approx. 15 at 5 ° C and approx. 10 at 0 ° C.

Die die Glaubersalz-Kühlungskristallisationsfällung bestimmenden Parameter wie Teilstrommenge und Temperatur, auf die gekühlt wird, können in einfacher Weise für die bei einer technischen Elektrolysezelle vorliegenden sonstigen Parameter angegeben werden.The parameters determining the Glauber's salt cooling crystallization precipitation, such as the partial flow quantity and the temperature to which cooling is carried out, can be specified in a simple manner for the other parameters present in a technical electrolysis cell.

Ist in einer Elektrolyseanlage beispielsweise ein Sulfatgehalt von 25 g/I tolerierbar, wird ferner ein Natriumchloridsalz mit 0,5 % Sulfatgehalt zur Aufstärkung einer Sole, die in der Elektrolysezelle um 40 g/1 verarmt wurde, eingesetzt, so ist ein Teilstrom von 2 % des Solestromes auf 5 °C abzukühlen, damit das bei der Auflösung von 40 g Salz pro 1 Sole eingeführte Sulfat entfernt wird. Bei stärkerer Abkühlung kann der Teilstrom für die Kühlungskristallisation kleiner gehalten werden. Bevorzugt erfolgt die Abkühlung der Sole in diesem zweiten Teilstrom auf Temperaturen zwischen -5 und 10 °C, besonders bevorzugt auf Temperaturen zwischen 0 und 5 °C.If, for example, a sulfate content of 25 g / l is tolerable in an electrolysis system, a sodium chloride salt with 0.5% sulfate content is also used to strengthen a brine that has been depleted in the electrolysis cell by 40 g / l, so a partial flow of 2% of the brine flow to 5 ° C to cool so that the sulfate introduced when 40 g of salt are dissolved per 1 brine is removed. With more cooling, the partial flow for the cooling crystallization can be kept smaller. The brine in this second partial stream is preferably cooled to temperatures between -5 and 10 ° C., particularly preferably to temperatures between 0 and 5 ° C.

Damit steht ein sicheres, die sonstigen Elektrolysebedingungen nicht beeinflussendes Verfahren zur Verfügung, das unter Verzicht auf Fällchemikalien eine ausreichende Sulfatentfernung aus der Sole gewährleistet, wobei das ausgefällte Sulfat ferner noch in Form einer direkt verwertbaren Sulfatverbindung als Glaubersalz anfällt.This provides a safe process which does not influence the other electrolysis conditions and which, without the use of precipitation chemicals, ensures sufficient sulfate removal from the brine, the precipitated sulfate also being obtained in the form of a directly usable sulfate compound as Glauber's salt.

Claims (6)

1. Process for the production of chlorine and sodium hydroxide solution from sulphate-containing sodium chloride salt by electrolysis, in which a sulphate-containing sodium chloride brine is circulated between the reduction of the content of sodium chloride in the brine in the electrolytic cell and the reconcentration of the brine by dissolving - sulphate-containing salt therein, the brine being dechlorinated, after leaving the electrolytic cell, by acidification with hydrochloric acid and the sulphate and other impurities introduced into the brine together with the salt being removed from the brine, characterised in that
a) a first partial stream is branched off from the brine cycle, to which partial stream the hydrochloric acid necessary for acidifying the brine is added, the partial stream is united with the brine main stream after a residence time which is sufficient for the decomposition of the chlorate which is formed during the electrolysis and is contained in the partial stream, and
b) a second partial stream is branched off from the brine stream, the second partial stream is cooled such that a quantity of Na2SO4 · 10H2O corresponding to the total quantity of sulphate introduced into the brine is crystallised out, the crystal slurry is separated off and the second partial stream is reunited with the brine main stream, and
c) in that, for the reconcentration, the brine is adjusted to a pH value of 6 to 8.5 by adding sodium hydroxide.
2. Process according to claim 1, characterised in that, after the reconcentration of the brine, the calcium ions introduced as an impurity together with the salt are first precipitated in the form of calcium carbonate by the addition of soda and then other impurities are precipitated by the further addition of sodium hydroxide and the precipitates are filtered off jointly.
3. Process according to claim 1 or 2, characterised in that a sulphate content of 10 to 30g/i, preferably 15 to 25 g/I is maintained in the brine cycle.
4. Process according to one of claims 1 to 3, characterised in that the brine in the second partial stream is cooled to - to 10 °C, preferably 0 to 5 °C.
5. Process according to one of claims 1 to 4, characterised in that 15 to 25 % strength hydrochloric acid is introduced into the first partial stream.
6. Process according to one of claims 1 to 5, characterised in that the volumetric stream of the first partial stream is equal to about half to double the hydrochloric acid necessary for the acidification of the brine for the dechlorination.
EP83103829A 1982-05-03 1983-04-20 Process for the electrolytic production of chlorine and caustic soda from salt containing sulphate Expired EP0093319B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823216418 DE3216418A1 (en) 1982-05-03 1982-05-03 METHOD FOR THE ELECTROLYTIC PRODUCTION OF CHLORINE AND SODIUM LYE FROM SULFATE-CONTAINING SALT
DE3216418 1982-05-03

Publications (3)

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EP0093319A2 EP0093319A2 (en) 1983-11-09
EP0093319A3 EP0093319A3 (en) 1984-02-08
EP0093319B1 true EP0093319B1 (en) 1986-07-30

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EP83103829A Expired EP0093319B1 (en) 1982-05-03 1983-04-20 Process for the electrolytic production of chlorine and caustic soda from salt containing sulphate

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JP (1) JPS58199882A (en)
DE (2) DE3216418A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3345898A1 (en) * 1983-12-20 1985-07-04 Bayer Ag, 5090 Leverkusen METHOD FOR REMOVING SULFATE FROM ELECTROLYSIS SOLE
US5028302A (en) * 1989-11-16 1991-07-02 Texas Brine Corporation Purification of chlor-alkali membrane cell brine
US5126019A (en) * 1989-11-16 1992-06-30 Texas Brine Corporation Purification of chlor-alkali membrane cell brine
GB9815173D0 (en) 1998-07-13 1998-09-09 Nat Power Plc Process for the removal of sulphate ions
CN112321046A (en) * 2020-09-24 2021-02-05 四川永祥股份有限公司 Salt recovery system for light brine and concentrated mother liquor

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3407128A (en) * 1967-03-13 1968-10-22 Ciba Ltd Process for the manufacture of chlorine, sodium hydroxide and hydrogen by the electrolysis of sodium chloride in mercury cells
FR2376907A1 (en) * 1977-01-06 1978-08-04 Kestner App Evaporateurs Extn. of Glauber's salt and common salt from lye of diaphragm cells - gives useful by=products and allows recycling of the lye
DE2837313A1 (en) * 1978-08-26 1980-03-13 Metallgesellschaft Ag METHOD FOR THE ELECTROLYSIS OF AQUEOUS ALKALI HALOGENIDE SOLUTIONS
DE3037818C2 (en) * 1980-10-07 1985-08-14 Hoechst Ag, 6230 Frankfurt Process for the production of sodium bisulfate

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JPS58199882A (en) 1983-11-21
EP0093319A2 (en) 1983-11-09
DE3216418A1 (en) 1983-11-03
DE3364877D1 (en) 1986-09-04
EP0093319A3 (en) 1984-02-08

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